First, rule out the innocent explanations
- Not enough was added — many vehicles need a substantial top-up before the level threshold is recognised
- The system needs a drive cycle — some vehicles only re-check level after ignition off, a wait, then a normal drive
- The fluid was poured into the wrong filler — a genuine and expensive mistake worth checking
- The AdBlue was old, frozen or of poor quality
If it's none of those, it's a system fault
- Level or quality sensor failure inside the tank
- Tank heater circuit faults, especially after cold weather
- Pump pressure faults so the fluid never gets dosed
- A crystallised dosing injector
- NOx sensor faults leading to efficiency codes that ignore level entirely
Why clearing it doesn't work
The system re-runs its self tests within a few drive cycles. Clear the code without fixing the cause and the light — and the countdown — returns.
We diagnose, repair, verify in live data, and clear the code last.
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